The present invention relates to the measurement of activity levels in human beings.
The measurement of the activity of human subjects is an essential quantification in behavioral research. Movement disorders such as Parkinson's disease and Huntington's chorea, hyperactivity in children, manic depressive illness, and other afflictions are all characterized by abnormal activity. Treatment many times involves the application of various drugs to subjects in an attempt to modify their behavioral activity patterns. One determination of the effectiveness of a particular drug treatment program is the ultimate affect on the individual's activity levels over a long period of time, twenty four hours or greater.
In the manic depressive illness, for example, a long depression is often followed by a rapid but brief return to the normal state, which in turn is followed by the sudden onset of manic behavior. The change from one state to another is called the "switch process" and is a very important research area. It is essential to have accurate activity data in order to show precisely when the switch occurs and to detail how drastic the change in behavioral activity is.
Many prior art methods have been employed to measure activity levels, including devices utilizing capacitive, ultrasonic and telemetric techniques. Each of these methods has advantages and disadvantages but they all require the subject to remain in a particular area. Devices which allowed the patient to move beyond a restricted area generally only provided indications of total physical activity and required numerous readings by trained personnel in order to get a reasonable time-base upon which activity levels can be projected. Furthermore, there are indications that even ward nurses in a retention facility were not positive as to the detecting of a difference in a subject's general activity level. Therefore, even if it were possible to have a subject under observation at all times, there would be no way of ensuring that the time the "switch" process occurs would be accurately recorded. Furthermore, it is extremely difficult through mere observation to determine quantitatively the violence or strength of a particular movement.